Boilers



Au'g. 2, 1960 Filed Fb. 10, 1958 FIGJ J. A. TATEM El'AL BOILERS 2 Sheets-Sheet 1 Aug. 2, 1960 Filed Feb. 10. 1958 J. A. TATEM ETI'AL BOILERS 2 Sheets-Sheet 2 LKS-'R United Wolverhampton, England assignors vto Orr 8: Sembower Incorporated, Rea Pa.

Filed Feb. 10, 1958, Ser. No. 714,314 Claims priority, application Great Britain Feb. 22, 1957 2 Claims. (Cl. 110-165) 'This invention relates to boilers and especially to boilers of the vself contaned type known as packaged boilers."

An object of the present invention is to provide a packaged boler which may be fired by pulverized fuel.

From one aspect, a boler unit in accordance with the invention comprises a fire tube boler fired |by a pulverized fuel burner, means for separating fly ash from the combustion gases during their passage through the boiler unit and for depositing them in a water trough to form a sludge, means for circulating the sludge in a closed circuit and means for delivering a proportion of the sludge to a remote sump or the like.

From another aspect, in a boler in accordance with the invention, fired with pulverized fuel the fiy ash is abstracted from the combustion gases during their passage through the boiler and deposited into a water trough, the water in this trough being circulated with the deposited ash in a closed circuit from which a proportion of the water and ash is continuously extracted and delivered to a sump.

From yet another aspect, the invention provides a boler unit comprising a pulverized fuel fired horizontal boiler, dust collecting means at each end of the boler delivering fly ash into a water trough running longitudinally below the boiler, this trough sloping downwardly from one end to a sump at the other, and a sludge pump arranged to draw sludge from this sump and return a proportion of it to the other end of the trough and to deli'ver the remainder of it to a distant disposal point.

The water trough may be formed in the concrete or other foundation on which the boler rests or may comprise a metal trough aflixed to the bottom of the boler unit and supplied therewith.

In -some cases, it may be desirable to include a gn't arrester in the boler stack and this is then conveniently arranged to discharge into the water trough.

Other parts of the invention. are embodied in the preferred form which will now be described in some detail by way of example with Vreferenceto the accompanying drawings in which i Fig. 1 is a side view of a boler unit partly in crosssection and Fig. 2 is an end view.

In this form, the boler 1 is of the packaged type, that is it comprises a self contaned steam generating unit which can be placed as a complete unit on prepared foundations 2 and requires only connection to feed water supply, and electricity supply to be ready for immediate use.

This boler comprises a horizontal fire tube boiler of the type having one or more passes and having at each end reversal chambers for the reversal of the gases. It is provided with a pulverized fuel burner 3 which is fed with fuel from a hopper 4 (or direct from a pulverized) by means of a blower 5. i

The burner 3 produces hot gases which are directed into the fire tubes and which carry with them fly ash resulting i" from the combstion of the fuel; `This fly'a'sh is'a-bstracted from thegases in the reversal chamber'siand is deposited into chutes 6, 7 one 'at each'end of the b'oiler 1. i J

Beneath the boiler '1 is a water trough 8 running longitudinally from end to end of the boler. This trough is of U-section or other section and slopes downwardly from the front to the rear of the boler. At the low end there is provided a sump 9 formed by increasing the depth of the trough 8.

The trough 8 may be formed in the concrete foundations 2 on which the unit 1 rests or it may be formed of metal and provided as part of the unit. In the later case, the concrete foundation may be suitably shaped to accommodate the trough.

On the boler unit is provided a sludge pump 10 drivem by an electric motor 11. The inlet 12 of this pump is connected to a pipe 13 having an open-ended leg 14 directed downwardly into the sump 9. The outlet 15 of the pump is connected to a pipe 16 having an open endecf leg 17 directed downwardly into the other end of the trough 8, forwardly of the chute 6 at the front end of the boler. A branch pipe 18 also leads from the outlet of the sludge pump and this pipe 18 may be as long as necessary to reach to a suitable depositing point for sludge. Both the outlet pipes 16 and 18 are controlled by 'valves 19, 20 so that the propoxtion of the pump output passing through either pipe may be controlled. Usually about 10% of the output is passed through the branch pipe 18 and the remaining is returned to the trough 8.

The sludge pump 10 draws sludge (comprisng a mixture of water and fly ash) from the sump and delivers most of it to the front end of the trough 8 from where it flows down the trough to the sump 9, thus setting up a closed circulation and washing any deposited fly ash into the sump. At the same time a proportion of the sludge is removed from the circulating system anddeposited outside the system. i

The arrangements s economical in its requirements for water for fly 'ash disposal since most of the water is used continuously. By removing a proportion of the sludge, the ash content of the circulating water is kept below a desrable limit, so long as the rate at which ash is removed through the branch pipe is at least equal to the rate at which ash is deposited in the trough. The ash density can be kept const-ant by electric or other automatic control.

Should some fly ash not be removed by the dust collectors in the boler, a grit arrestor 21 may be fitted in the stack pipe 23 and the dust collected in this may be deposited through a down pipe 22 into the sump 9.

It will be understood that the invention is not restricted? to the details of the preferred form described by way off example which may be modified without departure from the broad ideas underlying them.

vWe claim:

l. In a packaged pulverized fuel-fired horizontal fire tube boler, dust collecting means at each end of said boler, means defining a water trough extending beneath said boler substantially the full length thereof between said dust collecting means, the -bottom of said trough being inclined and having a sump at its lower end, chutes leading from each of said dust collecting means to the adjacent end of said trough, a pump, first conduit means connecting the inlet of said pump directly to said sump, second conduit means connectng the outlet of said pump directly to the end of said trough remote from said sump to provide a closed recirculating circuit, first valve means in said second conduit means for controlling the flow therethrough, third conduit means connected to said second conduit means intermediate the outlet of the pump and said first valve means and leading to a disposal point remote from said boler, and second valve means in said third conduit means to control the flow therethrough, said 

